1. Technical Field
Embodiments of the invention relate generally to electronic signal monitoring and more specifically to systems and methods for optimizing electrocardiography study performance.
2. Discussion of Art
Electrocardiography (ECG) studies record the electrical activity and pathways of a heart to identify, measure and diagnose arrhythmias. In particular, such studies measure electrical changes caused by the depolarization of the heart muscle during each heartbeat. To accomplish this, ECGs utilize electrodes that are combined into combinations, the output of which are referred to as a lead.
ECG leads are used in electrophysiology (EP) studies, which assess electrical activity through the use of catheters placed in the heart through veins or arteries. More specifically, surface ECG leads attached to the patient are used as the reference for the intra cardiac signals from the catheters. That is, they provide a voltage reference to the patient for measurement by other leads.
In this context, ECG leads may encounter noise from a variety of sources such as wireless electrical devices. Moreover, EP studies are typically combined with ablation therapy in which a catheter employs radiofrequency energy, for example, to treat arrhythmias. Various medical devices may also attached to a patient during an EP study potentially creating noise. In addition, ECG leads have to measure relatively small electrical signals from the patient, less than 20 uV in some instances. As will be appreciated, given the above considerations, achieving acceptable study recordings may be challenging.
To reduce noise, ECG systems often utilize a circuit design topology derived from a circuit commonly referred to as “driven right leg” or “right leg drive.” Right leg drive (RLD) circuitry is used to eliminate common mode interference noise and to ensure that recording system ground tracks with the patient. In general, RLD circuits introduce a signal into right leg of a patient to cancel common mode noise from the electrodes. There are currently several RLD circuit topologies that are configured and/or tuned for specific study conditions. As will be appreciated, however, a particular RLD circuit may offer suboptimal performance when it is used in an application that differs from the specific study conditions for which the circuit was originally configured/tuned, or when study conditions change.
It is desirable to provide an ECG system with user selectable and/or modifiable circuit topologies to optimize system performance in a wide variety of study conditions.